Lab Notes: Mice Made Sociable May Hold Autism Clue

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Lab Notes: Mice Made Sociable May Hold Autism Clue

Serotonin May Have Role in Autism

Mice with autism-like behavioral abnormalities became more outgoing and sociable

when treated with a drug that mimics serotonin activity.

When a " stranger " mouse was placed in their environment, mice treated with

buspirone showed greater interest in the newcomer and spent more time sniffing

the new mouse, as compared with animals that did not get the serotonergic drug.

The findings add to evidence implicating serotonin in at least some cases of

autism and related disorders, according to an article published in the Journal

of Neurochemistry. The results also suggest that drugs that increase brain

levels of serotonin may have a role in treating some patients with autism.

" No animal model is completely characteristic of humans, and we're far from

saying that buspirone is a treatment for behaviors of autistic people, "

Georgianna Gould, PhD, of the University of Texas Health Sciences Center at San

, said in a statement. " But this does offer further proof that serotonin

is involved in a significant proportion of autism cases. "

Serotonin may play a role in as many as a third of autism cases, Gould and her

co-authors noted in their article. Approved for treatment of anxiety and

depression, buspirone is a serotonin mimetic that partly replicates the

neurotransmitter's effects on receptors.

-- C.B.

Another Pandemic Flu Outcome: Tainted Water

Not only could people die by the millions if a highly virulent flu strain were

to become a pandemic, but there could be additional hazards too -- such as

contaminated drinking water.

Researchers at several institutions in the U.S. and Europe, led by

Singer, PhD, of the U.K. Centre for Ecology & Hydrology, developed a computer

model of flu pandemics of varying severity. It also included the likely rise in

drugs that would be handed out during pandemics and how much would end up the

Thames River basin -- through excretion and excess pills flushed down the loo

(or toilet as we say on the western shores of The Pond).

The concern is twofold, the researchers pointed out in Environmental Health

Perspectives.

First, people downstream would take in these drug molecules from their water and

resistant organisms may then flourish.

Second, the drugs would inhibit growth of microbes used in wastewater treatment.

In that event, sewage would be only partially treated before entering surface

waters, potentially causing an environmental disaster.

The model predicted that in even moderate pandemics, from 80% to 100% of

wastewater treatment plants would find that drug concentrations would reach

levels that impair treatment efficiency.

Moreover, up to 40% of the Thames estuary would show signs of environmental

toxicity.

-- J.G.

Possible Solution for Battlefield Blood Loss

An infusion of nitric oxide (NO) may be enough to reverse the effects of

potentially fatal blood loss, according to a study in Resuscitation.

Researchers at Albert Einstein College of Medicine in the Bronx, N.Y., designed

NO-releasing nanoparticles, which were then added to saline and infused into

hamsters that had lost half of their blood by another team at the University of

California San Diego.

Once in the bloodstream, the nanoparticles released a sustained dose of NO,

which prevented cardiovascular collapse by preserving cardiac stability and

microvascular perfusion. The NO reversed arteriolar vasoconstriction and

partially recovered both functional capillary density and microvascular blood

flows.

The treatment may someday translate into use on the battlefield and in other

trauma situations, the researchers noted in their paper.

" Our nanoparticle therapy may offer the potential for saving lives in those

situations. It's lightweight and compact and doesn't require refrigeration, "

said one of the study authors, Einstein's Friedman, MD, PhD, in a

statement.

-- T.N.

Gut Bugs Reach Further

" Good " bacteria in the gut may orchestrate metabolic functions not just in the

digestive tract but also in other organs, including the liver, researchers

reported in the open-access journal mBio.

The group exposed mice without any internal bacteria to bedding from normal mice

to watch what happened as the animals developed gut microbiota.

Over the first five days, the newly colonized mice gained 4% of their body

weight and showed rapid changes in how the liver metabolized glucose for

immediate use or storage as fat.

Gaining gut bacteria strongly stimulated an enzyme -- Cyp3a11 -- used by the

liver to metabolize medications, which could be an important finding if a

similar process occurs in humans, according to the researchers.

One group of bacteria, in particular, of the Coriobacteriaceae family, appeared

tied to the metabolic impact on the liver.

Kidney, colon, and plasma also showed effects of the gut microbiota.

The researchers cautioned about extrapolating these mouse results to humans but

suggested that the gut microbiota could be a route to boost processing of

nutrients and drugs.

-- C.P.

Kinase May Enhance Memory

There's no need for all that heavy equipment used by Jim Carey's character in

" Eternal Sunshine " to erode memories; many natural agents already impair their

encoding and consolidation, researchers say.

Yet few have been identified that can actually enhance memory. Now, a group from

the Weizmann Institute of Science in Israel has potentially identified one --

protein kinase M-Zeta (PKMZ).

In a previous study, the team found that inhibiting this kinase in the insular

cortex of rats erases long-term memory of a conditioned taste aversion up to at

least three months after encoding the memory. (Although it didn't affect the

rat's ability to subsequently relearn its taste aversion).

In this follow-up study reported in Science, the researchers either up- or

down-regulated expression of the protein, again in a murine model.

They found that rats with reduced levels of PKMZ had a marked reduction in

taste-aversion memory seven days later.

On the other hand, overexpression of PKMZ significantly enhanced long-term

memory after a week -- the rats that were trained to avoid a certain taste did

so more strongly.

The researchers aren't sure about the mechanisms, but it could be that

overexpression enhances attention or sensory or motor operations -- which aren't

memory per se, but are all required for memory expression. It could also enhance

memory retrieval.

Either way, the kinase may be a target not only for memory blockade (which would

be useful in treating posttraumatic stress disorder, for instance) but also for

novel memory enhancers that could aid in the treatment of amnesia or cognitive

decline.

-- K.F.

Shining Light on MS Pathogenesis

Researchers may be one step closer to puzzling out the mechanism that links

sunlight to multiple sclerosis.

In the current issue of the European Journal of Immunology, researchers led by

Colleen , PhD, of the University of Wisconsin in Madison, demonstrate that

the sunlight-dependent hormone 1,25-dihydroxyvitamin D3 blocks autoimmune T-cell

responses in MS through a direct effect on the T cells themselves.

MS researchers have long noted that the prevalence of the disease is lower in

places where people have a greater exposure to sunlight, and and

colleagues have previously shown -- in a mouse model of MS -- that vitamin D3

supplements slowed disease progression.

The current study looked at mice with an inactive vitamin D receptor on several

types of cells, including T cells, hematopoietic cells, and cells residing in

the central nervous system, and asked what happened when they were exposed to

the sunlight-dependent hormone.

Only the T cells played a role in disease progression, they found.

The findings suggest the possibility of vitamin D-based therapies for the

disease, and colleagues argued.

-- M.S.